A composite diaphragm quality detection equipment based on lithium battery production

Abstract

The application discloses a kind of composite diaphragm quality detection equipment based on lithium battery production, it is related to lithium battery production relevant technical field, including tensile testing station and be arranged on detection table drive mechanism, the power output end of the drive mechanism is arranged with two sets of clamping mechanism, two sets of clamping mechanism respectively clamps the two ends in composite diaphragm tensile direction, based on the driving action of drive mechanism, two sets of clamping mechanism relatively move, the clamping mechanism includes the drive plate being arranged on the power output end of drive mechanism and the extruding piece being arranged on drive mechanism, drive plate is equipped with clamping plate;In the tensile detection stroke of composite diaphragm, based on the extruding action of extruding piece, the clamping force of clamping plate to composite diaphragm gradually increases.

Description

Technical Field

[0001] This invention relates to the field of lithium battery production technology, specifically to a composite separator quality testing device based on lithium battery production. Background Technology

[0002] As is widely known, lithium batteries are the core energy carrier in new energy vehicles, energy storage devices, and consumer electronics, and their core component—the composite separator—is an indispensable part. The composite separator is mainly composed of a polyolefin-based membrane and functional coatings such as ceramics, PVDF, and aramid fibers. Its core function is to separate the positive and negative electrodes, allow lithium ions to migrate freely, and prevent electrons from passing through.

[0003] The production process of composite separators is complex, encompassing multiple stages such as base film preparation, coating, drying, and slitting. It is highly susceptible to various quality defects due to factors such as slurry characteristics, coating parameters, and equipment precision. Mechanical property testing, such as insufficient tensile strength, can lead to separator damage during battery winding, assembly, and use. Therefore, mechanical property testing is necessary during separator production. This is exemplified by the patent with publication number CN119534108B, publication date May 20, 2025, entitled "A Separator Mechanical Property Testing Device," which includes a base and a top seat fixedly connected. The top seat is equipped with a puncture mechanism for puncturing the separator; the base is equipped with a sample loading mechanism. This invention, by incorporating a sample loading mechanism, a puncture mechanism, a tensile mechanism, and a pressure distribution mechanism, allows for selection between tensile testing, puncture testing, and simultaneous puncture and tensile testing during diaphragm mechanical property testing. Furthermore, the conditions for each test can be controlled, providing more comprehensive and practically relevant test data for diaphragm mechanical testing, thus offering more complete and effective experimental data for evaluating diaphragm mechanical properties. Simultaneously, the sample loading mechanism effectively simplifies the disassembly and clamping steps of diaphragm samples, avoiding the time-consuming and labor-intensive problems associated with sample loading and unloading.

[0004] The shortcoming of the existing technology is that when the tensile strength of the composite diaphragm is tested, the two ends of the diaphragm become thinner under stress. Since the clamping position of the two ends of the composite diaphragm is relatively fixed, the clamping force is difficult to increase according to the change in thickness of the composite diaphragm when it is stretched. This causes the two ends of the composite diaphragm to tend to detach from the clamping position. If the two ends of the composite diaphragm detach from the clamping position, it will obviously affect the tensile strength test of the composite diaphragm. Even if they do not detach, it will significantly increase the error of the tensile strength test of the composite diaphragm. Summary of the Invention

[0005] The purpose of this invention is to provide a quality testing device for composite separators produced from lithium batteries, thereby solving the technical problems in related technologies. To achieve the above objective, this invention provides the following technical solution:

[0006] A quality testing device for composite separators produced from lithium batteries includes a tensile testing table and a drive mechanism mounted on the testing table. Two clamping mechanisms are arranged at the power output end of the drive mechanism, each clamping one end of the composite separator in the tensile direction. Based on the driving action of the drive mechanism, the two clamping mechanisms move relative to each other. Each clamping mechanism includes a drive plate mounted on the power output end of the drive mechanism and an extrusion member mounted on the drive mechanism. The drive plate is equipped with a clamping plate. During the tensile testing stroke of the composite separator, the clamping force of the clamping plate on the composite separator gradually increases due to the extrusion action of the extrusion member.

[0007] The aforementioned driving mechanism includes a housing mounted on a tensile testing table and a driving source located inside the tensile testing table. The housing contains two lead screws, each with two sections of threads rotating in opposite directions. Two driving plates are mounted on the two sections of threads rotating in opposite directions.

[0008] The aforementioned lead screw drives the drive plate to move at a speed of 200 mm per minute or 100 mm per minute, and the composite diaphragms of the same batch have a uniform stretching rate during tensile testing.

[0009] As described above, the portion of the clamping plate used to clamp the composite diaphragm has a V-shaped structure, and the end of the composite diaphragm is clamped within the opening of the V-shaped structure; under the extrusion action of the extruder, the opening of the V-shaped structure becomes smaller.

[0010] As mentioned above, flexible pads are installed on both sides of the inner wall of the V-shaped structure opening by bolts.

[0011] The extrusion member described above includes two sets of base plates corresponding to the two clamping plates respectively. Each set of base plates is fixed to the housing. Two extrusion rollers are symmetrically arranged on each set of base plates, and the corresponding clamping plate is located between the two extrusion rollers.

[0012] As mentioned above, the width of the flexible pad is greater than the width of the composite diaphragm.

[0013] As mentioned above, the housing is provided with an adjustment groove, and each set of base plates is fixed to the adjustment groove by bolts.

[0014] As described above, the opening ends of the V-shaped structure are all slidably provided with extrusion plates, and flexible pads are arranged on the flexible pads. The extrusion plate includes a first section that is extruded by the extrusion roller and a second section for pushing the flexible pads. The first section and the second section are connected by an elastic element. Based on the extrusion action of the extrusion roller, the extrusion plate pushes the flexible pads to adhere tightly to the composite diaphragm.

[0015] As described above, the area of ​​the flexible pad covering the composite diaphragm gradually increases along the width direction of the composite diaphragm.

[0016] The beneficial effects of this invention are as follows: by arranging the extruders, when performing tensile testing on the composite diaphragm, the clamping force of the clamping plate on the composite diaphragm can increase with the increase of the stretching distance. Thus, as the stretching distance gradually increases, the composite diaphragm becomes thinner at the clamping position and is difficult to detach from the clamping plate, thereby enabling better tensile strength testing and reducing testing errors. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0018] Figure 1 This is a three-dimensional structural schematic diagram of a composite membrane quality testing device based on lithium battery production provided in an embodiment of the present invention;

[0019] Figure 2 This is a three-dimensional structural diagram of the internal structure of a composite membrane quality testing device based on lithium battery production provided in an embodiment of the present invention;

[0020] Figure 3 This is a front view structural diagram of a composite membrane quality testing device based on lithium battery production provided in an embodiment of the present invention;

[0021] Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure at point AA;

[0022] Figure 5 for Figure 4 Enlarged structural diagram at point B in the diagram;

[0023] Figure 6 This is a first-view exploded view of the clamping mechanism of a composite membrane quality testing device based on lithium battery production, provided in an embodiment of the present invention.

[0024] Figure 7 This is a second-view exploded view of the clamping mechanism of a composite membrane quality testing device based on lithium battery production, provided in an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Tensile testing table; 2. Clamping mechanism; 20. Drive plate; 21. Clamping plate; 22. Flexible pad; 23. Base plate; 24. Extrusion roller; 25. Adjustment groove; 26. Extrusion plate; 260. First section; 261. Second section; 262. Elastic element; 27. Flexible pad; 3. Drive mechanism; 30. Housing; 31. Drive source; 32. Lead screw; 4. Composite diaphragm. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solution of the present invention, the following will be described in conjunction with the appendix. Figure 1 To be continued Figure 7 The present invention will now be described in further detail.

[0028] In this embodiment of the invention, a composite separator quality testing device based on lithium battery production is provided, including a tensile testing table 1 and a driving mechanism 3 disposed on the testing table. The power output end of the driving mechanism 3 is provided with two sets of clamping mechanisms 2, which respectively clamp the two ends of the composite separator 4 in the tensile direction. Based on the driving action of the driving mechanism 3, the two sets of clamping mechanisms 2 move relative to each other. The clamping mechanism 2 includes a driving plate 20 disposed on the power output end of the driving mechanism 3 and an extrusion member disposed on the driving mechanism 3. The driving plate 20 is provided with a clamping plate 21. During the tensile testing stroke of the composite separator 4, based on the extrusion action of the extrusion member, the clamping force of the clamping plate 21 on the composite separator 4 gradually increases.

[0029] Specifically, the tensile testing table 1 is equipped with an operating system for controlling the composite diaphragm 4 to perform tensile testing. The composite diaphragm 4 is an anisotropic material with significant differences in longitudinal and transverse strength, requiring separate sampling and testing. The width is generally 15mm or 25mm, and the length needs to meet the requirements of the clamping mechanism 2. The composite diaphragm 4 to be tested is basically cut into a rectangle. The clamping mechanism 2 can clamp the ends of the composite diaphragm 4 to be tested. One clamping mechanism 2 is configured at each end of the composite diaphragm 4. After the two opposite ends are clamped, the driving mechanism 3 drives the two sets of clamping mechanisms 2 to move away from each other, thereby realizing the tensile testing of the composite diaphragm 4.

[0030] The aforementioned shortcomings of the prior art are that when the composite diaphragm 4 is subjected to tensile strength testing, its two ends become thinner under stress. Since the clamping positions of the two ends of the composite diaphragm 4 are relatively fixed, the clamping force is difficult to increase according to the change in thickness of the composite diaphragm 4 when it is stretched. This causes the two ends of the composite diaphragm 4 to tend to detach from the clamping positions. If the two ends of the composite diaphragm 4 detach from the clamping positions, it will obviously affect the tensile strength testing of the composite diaphragm 4. Even if they do not detach, it will significantly increase the error of the tensile strength testing of the composite diaphragm 4.

[0031] Therefore, based on the above-mentioned technical problems, in this embodiment, the clamping mechanism 2 is improved to avoid the above situation. That is, each clamping mechanism 2 includes a drive plate 20, which is set at the power output end of the drive mechanism 3 and can move linearly (the drive mechanism 3 can be a cylinder, a lead screw transmission mechanism, etc.). Each drive plate 20 is provided with a clamping plate 21. The clamping plate 21 can first pre-clamp the end of the composite diaphragm 4. As the two drive plates 20 are driven away from each other, the clamping plate 21 is squeezed by the extruder, and the clamping force on the end of the composite diaphragm 4 also increases. The clamping plate 21 can be composed of two relatively movable plate-like structures. When squeezed by the extruder, they can move closer to each other (the extruder can be a cylinder as a power source to generate a thrust on the clamping plate 21 during the extension process). Thus, as the composite diaphragm 4 is stretched a longer distance, the clamping force on the end of the composite diaphragm 4 also increases.

[0032] In this embodiment, by arranging the extruders, when performing tensile testing on the composite diaphragm 4, the clamping force of the clamping plate 21 on the composite diaphragm 4 can increase with the increase of the stretching distance. Thus, as the stretching distance gradually increases, the clamped position of the composite diaphragm 4 becomes thinner and it is difficult to detach from the clamping plate 21, thereby enabling better tensile strength testing and reducing testing errors.

[0033] Preferably, the drive mechanism 3 includes a housing 30 mounted on the tensile testing table 1 and a drive source 31 disposed within the tensile testing table 1. The housing 30 is provided with two lead screws 32, each lead screw 32 having two sections of threads with opposite rotation directions. Two drive plates 20 are disposed on the two sections of threads with opposite rotation directions.

[0034] Specifically, the drive source 31 consists of a drive motor and a reducer. Two lead screws 32 are arranged vertically in parallel. The transmission between the lead screws 32 is through a gear and belt structure. The power output end of the reducer transmits power to one of the lead screws 32 through a coupling. The two lead screws 32 rotate in the same direction. Each lead screw 32 has two threads with opposite rotation directions. During the rotation of the lead screws 32, the two drive plates 20 located in different rotation directions can move relative to each other.

[0035] Preferably, the lead screw 32 drives the drive plate 20 to move at a speed of 200 mm per minute or 100 mm per minute, and the composite diaphragms 4 of the same batch have a uniform stretching rate when performing tensile testing; specifically, too fast a stretching rate will result in higher strength and lower elongation; too slow a stretching rate will result in scattered data, so it is necessary to strictly follow the requirements.

[0036] Furthermore, the portion of the clamping plate 21 used to clamp the composite diaphragm 4 has a V-shaped structure, and the end of the composite diaphragm 4 is clamped in the opening of the V-shaped structure; under the extrusion action of the extruder, the opening of the V-shaped structure becomes smaller.

[0037] Specifically, the V-shaped structure of the clamping plate 21 has a certain degree of toughness and can undergo elastic deformation to a certain extent when subjected to external force. Therefore, this characteristic is used to achieve the clamping action on the end of the composite diaphragm 4, that is, the squeezing action of the extruder makes the opening of the V-shaped structure smaller. However, this clamping of the end of the composite diaphragm 4 is a completely rigid clamping action. Although it can achieve the clamping action of the composite diaphragm 4, it is easy to damage the coating on the surface of the composite diaphragm 4, making the clamping surface smooth during the stretching process. Therefore, in an optional embodiment, flexible pads 22 are bolted to the inner walls on both sides of the V-shaped structure opening to prevent damage to the composite diaphragm. 4. During pre-clamping, the two flexible pads 22 in opposite positions can be brought closer together by tightening the bolts, preferentially clamping the end of the composite diaphragm 4. During the subsequent tensile test, as the tensile distance increases, the V-shaped structure opening gradually decreases due to the squeezing action of the extruder, and the clamping force on the end of the composite diaphragm 4 also increases. When the flexible pad 22 undergoes elastic deformation under external force, its effective clamping area also increases, thereby providing more contact area for clamping the end of the composite diaphragm 4. Preferably, the width of the flexible pad 22 is greater than the width of the composite diaphragm 4 to ensure that the end of the composite diaphragm 4 is completely clamped.

[0038] Preferably, the extrusion member includes two sets of base plates 23 corresponding to the two clamping plates 21 respectively. Each set of base plates 23 is fixed to the housing 30. Two extrusion rollers 24 are symmetrically arranged on each set of base plates 23, and the corresponding clamping plate 21 is located between the two extrusion rollers 24.

[0039] Specifically, each set of substrates 23 consists of two substrates, symmetrically arranged on the housing 30, with two extrusion rollers 24 positioned between them. The distance between the two extrusion rollers 24 is not adjustable. When the V-shaped structure of the clamping plate 21 passes through the area between the two extrusion rollers 24, it is subjected to the extrusion action of the two extrusion rollers 24, causing the opening of the V-shaped structure to become smaller. In order to accommodate different sizes or when performing a width-direction stretch test on another batch of composite diaphragms 4 after performing a length-direction stretch test on the composite diaphragm 4, the position of each set of substrates 23 on the housing 30 can be adjusted. Therefore, in an optional embodiment, an adjustment groove 25 is provided on the housing 30, and each set of substrates 23 is fixed in the adjustment groove 25 by bolts. The bolts are easy to disassemble, so the position of the substrates 23 can be easily adjusted as needed.

[0040] In this embodiment, after the composite diaphragm 4 is clamped, the tensile force acts on the entire end, but the corner is a stress abrupt change point. The force lines converge, compress, and superimpose here, and the local stress is much greater than that of the straight edge. Therefore, when subjected to external force, the corner is the first to yield, stretch, and thin. Thus, in the preferred embodiment, the opening end of the V-shaped structure is slidably provided with a squeezing plate 26, and the flexible pad 22 is provided with a flexible pad 27. The squeezing plate 26 includes a first section 260 squeezed by the squeezing roller 24 and a second section 261 for pushing the flexible pad 27. An elastic element 262 is connected between the first section 260 and the second section 261. Based on the squeezing action of the squeezing roller 24, the squeezing plate 26 pushes the flexible pad 27 to adhere tightly to the composite diaphragm 4.

[0041] Specifically, the flexible pad 27 is equivalent to the extension of the corresponding connected flexible pad 22. The flexible pad 22 is squeezed when the V-shaped structure opening becomes smaller, and its clamping rigidity is relatively strong. The clamping rigidity of the flexible pad 27 is relatively weak due to the pushing action of the extrusion plate 26 (since the extrusion plate 26 is divided into a first section 260 and a second section 261, and an elastic element 262 is provided between the first section 260 and the second section 261). The former is to prevent the composite diaphragm 4 from falling off when stretched, while the latter can provide flexible clamping at the edge position of the part of the composite diaphragm 4 clamped by the V-shaped structure opening, which can make the pressure distribution more uniform. It is equivalent to providing a flexible clamping part at the front end of the rigid clamping, which provides protection for the clamped part at the end of the composite diaphragm 4. In an optional embodiment, the area of ​​the flexible pad 27 covering the composite diaphragm 4 gradually increases along the width direction of the composite diaphragm 4. Thus, the coverage area at the corner position is larger than that of the rest, which can better maintain the friction at the corner, thereby avoiding the problem of premature falling off at the corner.

[0042] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of the claims of the present invention.

Claims

1. A quality testing device for composite separators produced from lithium batteries, comprising a tensile testing table and a driving mechanism disposed on the testing table, wherein two sets of clamping mechanisms are arranged at the power output end of the driving mechanism, the two sets of clamping mechanisms respectively clamping both ends of the composite separator in the tensile direction, and the two sets of clamping mechanisms moving relative to each other based on the driving action of the driving mechanism, characterized in that, The clamping mechanism includes a drive plate disposed on the power output end of the drive mechanism and an extrusion member disposed on the drive mechanism, and the drive plate is provided with a clamping plate. During the tensile testing of the composite diaphragm, the clamping force of the clamping plate on the composite diaphragm gradually increases due to the squeezing action of the extruder.

2. The composite membrane quality testing equipment based on lithium battery production according to claim 1, characterized in that, The drive mechanism includes a housing mounted on a tensile testing table and a drive source located inside the tensile testing table. The housing contains two lead screws, each with two sections of threads rotating in opposite directions. Two drive plates are mounted on the two sections of threads rotating in opposite directions.

3. The composite membrane quality testing equipment based on lithium battery production according to claim 2, characterized in that, The lead screw drives the drive plate to move at a speed of 200 mm per minute or 100 mm per minute, and the composite diaphragms of the same batch have a uniform stretching rate when subjected to tensile testing.

4. The composite membrane quality testing equipment based on lithium battery production according to claim 1, characterized in that, The clamping plate has a V-shaped structure for clamping the composite diaphragm, and the end of the composite diaphragm is clamped in the opening of the V-shaped structure; under the extrusion action of the extruder, the opening of the V-shaped structure becomes smaller.

5. The composite membrane quality testing equipment based on lithium battery production according to claim 4, characterized in that, Flexible pads are bolted to the inner walls on both sides of the opening of the V-shaped structure.

6. The composite membrane quality testing equipment based on lithium battery production according to claim 4, characterized in that, The extrusion component includes two sets of base plates corresponding to the two clamping plates respectively. Each set of base plates is fixed to the housing. Two extrusion rollers are symmetrically arranged on each set of base plates, and the corresponding clamping plate is located between the two extrusion rollers.

7. The composite membrane quality testing equipment based on lithium battery production according to claim 5, characterized in that, The width of the flexible pad is greater than the width of the composite diaphragm.

8. The composite membrane quality testing equipment based on lithium battery production according to claim 6, characterized in that, The housing has an adjustment groove, and each set of base plates is fixed to the adjustment groove by bolts.

9. The composite membrane quality testing equipment based on lithium battery production according to claim 7, characterized in that, The V-shaped structure has a slidable extrusion plate at the open end, and a flexible pad is arranged on the flexible pad. The extrusion plate includes a first section that is extruded by the extrusion roller and a second section for pushing the flexible pad. The first section and the second section are connected by an elastic element. Based on the extrusion action of the extrusion roller, the extrusion plate pushes the flexible pad to adhere tightly to the composite diaphragm.

10. The composite membrane quality testing equipment based on lithium battery production according to claim 9, characterized in that, The area of ​​the flexible pad covering the composite diaphragm gradually increases along the width direction of the composite diaphragm.

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